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Biomedical subjects

James W Albers

Publications and source records attributed to James W Albers.

7 recordsLinked to original sources
PubMed2006

Survey of electrodiagnostic laboratories regarding hemorrhagic complications from needle electromyography.

Little is known about the complications of needle electromyography (EMG) performed on anticoagulated patients, and no guidelines exist regarding its performance. We conducted an anonymous survey of academic EMG laboratories in the U.S. to understand current practices and complications with regard to anticoagulated patients and those receiving antiplatelet medications. Forty-seven (78%) of 60 EMG laboratories responded to the survey. Four laboratories (9%) reported at least one hemorrhagic complication requiring medical or surgical intervention in an anticoagulated patient, whereas none reported a hemorrhagic complication in patients receiving antiplatelet medications. Ten (21%) reported willingness to evaluate cranial, paraspinal, and all limb muscles in anticoagulated patients. This survey suggests that hemorrhagic complications from needle EMG of anticoagulated patients are rare. It also suggests that needle EMG of patients receiving antiplatelet therapy is not associated with increased reports of hemorrhagic complications.

Academic Medical Centers↗
PubMed2005

Amalgam exposure and neurological function.

Concerns regarding the safety of silver-mercury amalgam fillings continue to be raised in the absence of any direct evidence of harm. The widespread population exposure to amalgam mandated that a thorough investigation be conducted of its potential effects on the nervous system. The National Institute of Dental and Craniofacial Research and U.S. Air Force investigators collaborated in the ongoing Air Force Health Study (AFHS) of Vietnam era veterans. The primary study question involved adverse health effects associated with exposure to herbicides or dioxin. An assessment of exposure to dental amalgam fillings was added to the 1997-1998 health examination to investigate possible associations between amalgam exposure and neurological abnormalities. Our study population consisted of 1663 dentate AFHS participants, comprised of 986 AFHS controls and 677 Ranch Hand veterans who were exposed to dioxin in Vietnam. Two hundred and fifty-two of the participants had confirmed diabetes mellitus. Study outcomes included clinical neurological signs, vibrotactile thresholds, and summary variables for different levels of peripheral neuropathy. A limitation of our study is that our database did not include more sensitive continuous measures such as nerve conduction studies. No significant associations were found between amalgam exposure and clinical neurological signs of abnormal tremor, coordination, station or gait, strength, sensation, or muscle stretch reflexes or for any level of peripheral neuropathy among our study participants. A statistically significant association was detected between amalgam exposure and the continuous vibrotactile sensation response for the combined non-diabetic participants and separately for non-diabetic AFHS controls. No significant association in this measure was detectable for non-diabetic Ranch Hand veterans or among the combined diabetic participants. The association is a sub-clinical finding that was not associated with symptoms, clinically evident signs of neuropathy, or any functional impairment. Overall, we found no association between amalgam exposure and neurological signs or clinically evident peripheral neuropathy. Our findings do not support the hypothesis that exposure to amalgam produces adverse, clinically evident neurological effects.

Dental Amalgam↗
PubMed2004

Absence of sensory neuropathy among workers with occupational exposure to chlorpyrifos.

Several studies have reported the occurrence of sensory neuropathy with exposure to chlorpyrifos and other organophosphorus insecticides, at levels not associated with overt toxicity. We evaluated 113 chemical workers, including 53 of 66 (80%) eligible chlorpyrifos workers and 60 of 74 (81%) randomly selected referent workers, to identify evidence of sensory neuropathy or subclinical neuropathy. Compared to referents, chlorpyrifos subjects had significantly longer duration of work in chlorpyrifos-exposed areas (9.72 vs. 0.01 years; P < 0.0001), greater cumulative chlorpyrifos exposure (64.16 vs. 0.69 mg/m(3). day; P < 0.0001), higher urine 3,5,6-trichloro-2-pyridinol (TCP) excretion (108.6 vs. 4.3 microg/g creatinine; P < 0.0001), and lower plasma butyrylcholinesterase (BuChE) activity (7281 vs. 8176 mU/ml; P = 0.003). Despite exposures among chlorpyrifos subjects to levels at which well-described physiological effects on B-esterases exist, the frequency of symptoms or signs of neuropathy did not differ significantly between groups, and the only 2 subjects fulfilling criteria for confirmed neuropathy were both in the referent group. Mean nerve conduction study results were comparable to established control values and did not differ significantly between groups. We found no evidence of sensory neuropathy or isolated peripheral abnormalities among subjects with long-term chlorpyrifos exposure at levels known to be associated with the manufacturing process.

Adolescent↗
PubMed2004

Porphyric neuropathy.

The hepatic porphyrias are a group of rare metabolic disorders characterized by enzymatic defects in the biosynthesis of heme, a metalloporphyrin that is the principal product of porphyrin metabolism. The hepatic porphyrias are genetically transmitted as autosomal-dominant disorders with variable expression that produce a particularly severe form of neuropathy. Most medical students readily recognize acute attacks of porphyria when the classic triad of abdominal pain, psychosis, and neuropathy is present. Yet, porphyric neuropathy is a source of confusion in practice, and patients with porphyria rarely receive the correct diagnosis early in the course of the illness. Porphyric neuropathy is manifest by symptoms, signs, and cerebrospinal fluid abnormalities resembling acute Guillain-Barré syndrome. However, accompanying psychological features, a proximal predilection of asymmetric weakness, and electrodiagnostic findings indicative of an axonal polyradiculopathy or neuronopathy all suggest the diagnosis of porphyria. Confirmation of the diagnosis depends on use of appropriate laboratory studies. The underlying pathophysiology of porphyric neuropathy has not been established, but it may be related to direct neurotoxicity of elevated levels of delta-aminolevulinic acid. The severity of the neuropathy and the availability of potential treatments, including avoidance of provocative factors, make identification important.

Animals↗
PubMed2004

The effects of occupational exposure to chlorpyrifos on the neurologic examination of central nervous system function: a prospective cohort study.

Questions persist about adverse effects such as impaired cognition and attention, incoordination, spasticity, or parkinsonism from chronic, low-level exposures to organophosphate (OP) compounds. In a prospective cohort study, we evaluated chlorpyrifos-manufacturing workers and a referent group on 2 occasions, 1 year apart, to determine whether occupational exposure to chlorpyrifos produced clinically evident central nervous system (CNS) dysfunction. Chlorpyrifos subjects had significantly higher TCP excretion and lower average BuChE activity than referents in a range in which physiological effects on B-esterases exist. Few subjects had neurologic symptoms or signs, and there were no significant group differences in terms of signs at baseline or second examinations. Chronic chlorpyrifos exposure produced no clinical evidence of cortical, pyramidal tract, extrapyramidal, or other CNS dysfunction among chlorpyrifos subjects compared with referents, either at baseline or after 1 year of additional chlorpyrifos exposure.

Adult↗
PubMed2002

Electrodiagnostic approach to the patient with suspected peripheral polyneuropathy.

Peripheral neuropathy has a multitude of potential causes, which at times may make a clinician feel overwhelmed. This often leads to the performance of a number of costly investigations in the hope of finding an explanation or treatable cause for the neuropathy. The authors propose that by performing a thorough history and physical examination in conjunction with findings on electrodiagnostic studies, a rational and limited differential diagnosis may be generated so that a targeted and cost effective investigation may be performed.

Diagnosis, Differential↗